This invention generally relates to a temperature sensing system in the engine of a motor vehicle. More specifically, this invention relates to a temperature sensing device installed in the cylinder head of an engine of a motor vehicle.
Modern automotive engines typically rely on numerous engine parameters for correct engine operation. Optimum engine parameters are generally stored in the memory of an engine controller. Sensors on the engine are used to sense actual engine parameters while the controller compares these sensed values to the stored optimum valves. As a result, it is important that a reliable, repeatable sensor be installed in the engine having little engine-to-engine variation, such that a correct engine operating parameter is sensed.
Various sensors for sensing the temperature of a rigid body, such as a cylinder head of an internal combustion engine, have been developed. The sensor must be in intimate thermal contact with the rigid body to sense the proper temperature. To provide good thermal conductivity, some sensor designs utilize a spring such that, when installed, the spring provides a force to bias the sensor into contact with the rigid body to establish adequate thermal conductivity. Still other sensor designs rely on the mounting threads to provide the conductive path between the rigid body and the sensor. However, the previous temperature sensors have not provided an accurate reading of the temperature parameters in the cylinder head of an engine.
In accordance with one aspect of the invention a temperature sensing device and method of forming the same that improves the temperature reading capabilities in a cylinder head of the engine in an automobile is provided.
Yet another aspect of the invention is to have a temperature sensing device installed in the cylinder head having a closed portion and an extended portion. Preferably, the closed portion defines a cavity. An insert formed of a resin is inserted into the cavity. The insert preferably has a temperature sensing portion and a connector portion. The temperature sensing portion has a sensing element disposed in the insert. The insert ensures that the sensing element is in contact with the housing.
In accordance with another aspect of the invention when the housing having the insert and the sensing element is inserted into the cylinder head the extended portion of the housing is axially deformed such that the housing is in thermal contact with the cylinder head.